Apple M1 GPU compute with combined GPU and CPU uses an enormous amount of memory #97081

New Issue

Caden Mitchell · 2022-04-05T18:31:50+02:00

Caden Mitchell commented

2022-04-05 18:31:50 +02:00

System Information
Operating system: macOS Monterey 12.3
Graphics card: Apple M1 10-core
CPU: Apple M1 8-core

Blender Version
Broken: 3.2.0 Master

Short description of error
In Cycles, a scene that uses ~4.5 GB of memory in CPU and ~15 GB in GPU compute will use up to 75 GB of memory when combining the two together. I cannot attach the scene as it is far too complex and is proprietary. However, I imagine you could use the more complex demo files from the Blender website to see this result. Also, Blender will report about half the amount of memory being used in the render when doing an exclusively GPU render. So the Activity Monitor shows Blender using >14 GB, and Blender reports ~7.5 GB in the render interface.

Exact steps for others to reproduce the error
Load up a large scene for render. Ideally, something with lots of reflective materials, motion blur, and maybe volumetrics, too. Render using CPU, GPU, and then a combination to see the different effects it has on memory usage.

**System Information** Operating system: macOS Monterey 12.3 Graphics card: Apple M1 10-core CPU: Apple M1 8-core **Blender Version** Broken: 3.2.0 Master **Short description of error** In Cycles, a scene that uses ~4.5 GB of memory in CPU and ~15 GB in GPU compute will use up to 75 GB of memory when combining the two together. I cannot attach the scene as it is far too complex and is proprietary. However, I imagine you could use the more complex demo files from the Blender website to see this result. Also, Blender will report about half the amount of memory being used in the render when doing an exclusively GPU render. So the Activity Monitor shows Blender using >14 GB, and Blender reports ~7.5 GB in the render interface. **Exact steps for others to reproduce the error** Load up a large scene for render. Ideally, something with lots of reflective materials, motion blur, and maybe volumetrics, too. Render using CPU, GPU, and then a combination to see the different effects it has on memory usage.

Caden Mitchell commented

2022-04-05 18:31:50 +02:00

Added subscriber: @Caden-Mitchell

Ryda commented

2022-05-25 20:26:54 +02:00

Added subscriber: @Ryda42

Germano Cavalcante commented

2022-05-29 15:17:05 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2022-05-29 15:17:05 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Germano Cavalcante commented

2022-05-29 15:17:05 +02:00

I cannot reproduce this problem.
It must depend on the scene.
In the one I tested, the memory used with GPU + CPU was actually less than GPU only.

Please try the latest daily build: https://builder.blender.org/download/

If the problem persists, please give us more clear instructions on how to reproduce it from scratch.

I cannot reproduce this problem. It must depend on the scene. In the one I tested, the memory used with GPU + CPU was actually less than GPU only. Please try the latest daily build: https://builder.blender.org/download/ If the problem persists, please give us more clear instructions on how to reproduce it from scratch.

Caden Mitchell commented

2022-06-13 09:41:24 +02:00

A lot of development has happened since I opened this issue. I will try to prepare a demo file to see if I can reproduce this. Apologies for the late reply.

Caden Mitchell commented

2022-06-13 14:50:32 +02:00

Blender still reports memory wrong. I will add a demo file when I have time. For now, here is a screenshot. In it, you can see Blender thinks the most memory it's used is 3002 MB, when it is currently using ~13 GB. This is macOS Monterey 12.4, latest source from Git built hours ago. This is a CPU+GPU render.

Blender still reports memory wrong. I will add a demo file when I have time. For now, here is a screenshot. In it, you can see Blender thinks the most memory it's used is 3002 MB, when it is currently using ~13 GB. This is macOS Monterey 12.4, latest source from Git built hours ago. This is a CPU+GPU render. ![Screen Shot 2022-06-13 at 6.48.40 AM.png](https://archive.blender.org/developer/F13156110/Screen_Shot_2022-06-13_at_6.48.40_AM.png)

Thomas Dinges commented

2022-12-15 16:59:07 +01:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2022-12-15 16:59:07 +01:00

Is this still an issue in Blender 3.4?

Philipp Oeser removed the

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Apple M1 GPU compute with combined GPU and CPU uses an enormous amount of memory #97081